DataGrid入门级有关问题，求教

DataGrid入门级问题，求教
这是XAML代码

XML code

<navigation:Page xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"           x:Class="SLClient.Test"            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"            xmlns:d="http://schemas.microsoft.com/expression/blend/2008"           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"           mc:Ignorable="d"           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"           d:DesignWidth="640" d:DesignHeight="480"           Title="Test Page">    <Grid x:Name="LayoutRoot">        <data:DataGrid  Name="dataGrid" Margin="3,3,3,3"></data:DataGrid>    </Grid></navigation:Page>

C# code

using System.Net;using System.Windows;using System.Windows.Controls;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Animation;using System.Windows.Shapes;using System.Windows.Navigation;namespace SLClient{    public partial class Test : Page    {        public Test()        {            InitializeComponent();            List<DataItem> datas = new List<DataItem>();            datas.Add(new DataItem { ID = "1", Text = "item1" });            datas.Add(new DataItem { ID = "2", Text = "item2" });            datas.Add(new DataItem { ID = "3", Text = "item3" });            this.dataGrid.ItemsSource = datas;        }    }    class DataItem    {        public String ID { get; set; }        public String Text { get; set; }    }}

C# code

 public class DataItem    {        public String ID { get; set; }        public String Text { get; set; }    }